1. Field of the Invention
The present invention relates generally to infusion devices. More particularly, the invention concerns a novel, closed-system, combination infusion and flush set which enables safe administration of both medicaments and flush solutions with great accuracy using conventional large volume parenteral bags.
2. Discussion of the Invention
Various types of fluid administration sets have been suggested in the past for the therapeutic introduction into a patient of numerous types of fluids. For example, prior art administration sets are typically used to deliver fluids intravenously (IV sets) and usually are sterile, pyrogen-free and disposable. Although the construction of the administration sets vary somewhat from manufacturer to manufacturer, they all have certain basic components. These include a spike to pierce the rubber closure or plastic seal on the solution container, a drip chamber to trap air and permit adjustment of flow rate and a length of polyvinyl chloride tubing terminating either in a gum-rubber injection port or in a luer connector. An adjustable clamp on the tubing pinches the tubing to regulate flow. However, this approach to flow regulation and control is crude and often unreliable either because of clamp malfunction, human error, or both.
Intravenous fluids, which are sterile solutions typically of simple chemicals such as sugars, amino acids or electrolytes, are commonly used for a number of clinical conditions including correction of disturbances in electrolyte balance, correction of disturbances in body fluids (fluid replacement), and use as anti-bacterials, and vehicles for other medications and drug substances.
In the past, the intermittent administration to the patient of multiple fluids has been accomplished either through direct intravenous injection, or through the use of "piggybacking" wherein a second container is interconnected with the venipuncture site of the administration set via a "Y" site. In practicing this technique, one port of the "Y" site is connected to the tubing of the administration set, one port is connected to the second container, and the third port of the Y site is connected to the venipuncture site. When the prior art administration set is to be used in piggyback administration, the set is typically provided with a built-in check valve. When the piggyback is connected to the set and started, the check valve automatically closes off the primary infusion. When the piggyback runs out, the check valve automatically opens, thereby restarting the primary infusion.
In accordance with the prior art practices, when it is necessary to flush the system with a saline solution, or the like, the closure on the flush solution container is pierced with the spike of the administration set, the clamp is opened and the flush solution is allowed to flow by force of gravity through the delivery line. This practice must be closely monitored by competent medical personnel to insure that the flow of the flush solution toward the patient is precisely controlled. Since the uncontrolled flow of the flush solution to the patient can be potentially catastrophic, great care must be taken to prevent free flow of the flush solution toward the patient.
A recent development in the administration of medications to patients incorporates the use of a mechanical syringe pump. A pre-filled syringe is placed in an apparatus, which is programmed to depress the plunger of the syringe at a fixed rate over a fixed period of time. Use of a syringe pump is particularly useful in administration of medications over a period of time where a single bolus injection of medication cannot be tolerated by the patient. It is common practice to flush the IV line with any number of sterile flush solutions, such as saline, in order to administer the full dose of medication to the patient.
In certain patients, particularly neonates, the amount of medication is small and the residual medication in the line which must be flushed may account for a significant percentage of medication prescribed. If the syringe pump is used to slowly deliver medication over time, the use of a bolus flush to clear the residual medication in the line makes little sense as, for example, 60% of the drug may be give over 15 minutes and the remaining 40% which is the residual volume in the IV line which, with a bolus flush, may be administered in 15 seconds. In order to administer the full amount of medication slowly, the flush solution may be administered by the syringe pump. Prior to the present invention, a new syringe with the correct flush solution had to be prepared by the hospital's pharmacy, distributed to the correct patient, and placed in the syringe pump. The prior art was time consuming, costly, prone to error and raised the possibility of contaminating the patient by medical personnel inadvertently touching the connection points.
In the past, a second container containing the flush solution, may have been available at the bedside to allow medical personnel to draw up the flush solution. This required the use of needles to enter the container adding cost and the possibility of needle sticks. Also, if the flush container became contaminated due to periodic re-entering the container with a needle, the patient could become infected when the flush solution was administered.
Also, in the past, a second container containing the flush solution, could be connected to the patient administration IV Set via a four-way valve or stop cock. After the syringe in the pump was empty of its medication, medical personnel would open a fluid path from the syringe to the container of flush solution and draw up the flush solution into the syringe. The fluid path would then be opened from the syringe to the patient and the syringe pump set to slowly administer the flush solution. Such a system eliminates the need for pre-filled syringes as in the prior example. It also eliminated the need for needles to re-enter a bag of flush solution by the bedside. However, if the fluid pathway was incorrectly opened between the flush solution and the patient, an uncontrolled flow of flush solution to the patient could result with a potential catastrophic result.
The apparatus of the present invention elegantly overcomes various drawbacks of prior art administration sets by providing within the system a stop cock of unique design that positively controls the direction of flow of both IV and flush solutions to the patient. More particularly, as will become apparent from the description which follows, the novel design of the apparatus of the present invention provides a positive control, closed system which uses a syringe pump for administration of both intravenous drugs and flush solutions. With the apparatus of the invention, fluid flow can be precisely regulated and conventional large volume parenteral bags can safely be used for line flush without fear of possible free flow of the flush solution to the patient.